1. Technical Field
Aspects of the present invention relate to a print data generating device, a method to generate print data, and a computer usable medium therefor, and more specifically, to a device, a method, and a computer usable medium to generate print data which is suitable for printing an image in inks including white ink.
2. Related Art
Conventionally, an inkjet printing apparatus, which ejects a plurality of colors of inks and white ink onto a recording medium, has been known. In the inkjet printing apparatus, the inks are drawn from ink reservoirs to a plurality of ejecting channels provided in an inkjet head and ejected from nozzles at the end of the ejecting channels when actuators such as heater elements and piezoelectric elements are selectively activated. When an image is formed in colors, each of pixels composing the image is resolved, for example, into the three primary colors, which are cyan (C), magenta (M), and yellow (Y), thereafter, a colored pixel is formed as the inks adjusted in their densities are ejected onto the recording medium. In addition, a pixel in a black color is reproduced by blending the colored inks or using black (K) ink. Further, opaque white (W) ink can be used to reproduce white pixels and to form a base layer on a dark-colored (i.e., black) recording medium so that pixels in the three primary colors (transparent) can be reproduced clearly over the base layer regardless of a color of the recording medium. Thus, images reproduced in higher quality can be obtained without being limited by colors and lightness of the recording media.
When drops of the inks ejected from the nozzles are missed or blotted out of intended positions upon printing, the quality of the image can be undesirably degraded. In order to avoid the blots, methods to align the positions of the ink drops to be ejected have been suggested; however, accurate positioning of the ink drops has been yet difficult. Moreover, such methods do not dissolve blots, and the problem caused by the blots remains unsolved. In order to overcome blots of black ink specifically, methods to adjust amounts of colored inks in outline areas which are in black have been suggested in, for example, Japanese Patent Provisional Publications Nos. 2001-199089 and 2000-232590.